Apparatus for hot-stretching steel wire and cable

ABSTRACT

A pair of spaced caterpillars along a moving direction of steel wire or steel cable to be stretched, comprises a pair of chainrollers which compressively contact each other and rotate in opposite directions. A heating apparatus is disposed between the caterpillars and a cooling apparatus is also disposed at another position between the caterpillars. One caterpillar is disposed forwardly of the other caterpillar in the moving direction of the steel wire or cable and driven at a higher velocity than that of the other caterpillar so that a predetermined tension is applied on the moving steel wire or cable between the caterpillars. Each chain-roller of the pair includes holder members which are provided in facing relation to and urged, under liquid pressure, against those of the other chain-roller. Each of the holder members has an upper part holding the steel wire or steel cable and a lower part connected to the chain-roller, the parts being formed of metal, and the upper part is supported by the lower part through a resilient plate.

United States Patent n91 Takeo et al.

[ APPARATUS FOR HOT-STRETCHING STEEL WIRE AND CABLE [75] inventors:Keinosuke Takeo, Osaki; Tomoaki Katsumata; Akimitsu Hijikata, both ofltami, all of Japan 73] Assignee: Sumitomo Electric Industries, Ltd.,

Osaka, Japan [22] Filed: Aug. 7, 1972 [21] Appl. N0.: 278,323

[30] Foreign Application Priority Data Aug. 7, 1971 Japan 46/70839 [52]US. Cl 72/342, 72/17, 72/378,

[51] Int. Cl B2lf 9/00 [58] Field of Search.... 140/2; 72/17, 287, 342,378; 266/3; 226/172, 186

[ Jan. 29, 1974 3,469,829 9/1969 Fujita et al 140/2 P imqryNEmmm H Q U ase Zinn and Macpeak 5 7 1 ABSTRACT A pair of spaced caterpillars along amoving direction of steel wire or steel cable to be stretched, comprisesa pair of chain-rollers which compressively contact each other androtate in opposite directions. A heating apparatus is disposed betweenthe caterpillars and a cooling apparatus is also disposed at anotherposition between the caterpillars. One caterpillar is disposed forwardlyof the other caterpillar in the moving direction of the steel wire orcable and driven at a higher velocity than that of the other caterpillarso that a predetermined tension is applied on the moving steel wire orcable between the caterpillars. Each chain-roller of the pair includesholder members which are provided in facing relation to and urged, underliquid pressure, against those of the other chain-roller. Each of theholder members has an upper part holding the steel wire or steel cableand a lower part connected to the chain-roller, the parts being formedof metal, and the upper part is supported by the lower part through aresilient plate.

2 Claims, 3 Drawing Figures APPARATUS FOR HOT-STRETCI-IING STEEL WIREAND CABLE BACKGROUND OF THE INVENTION 1. Field of the Invention Thepresent invention relates to an apparatus of manufacturing at least onesteel wire or steel cable having a small relaxation, particularly steelwire or steel cable suitable to be used as steel tendons in prestressedconcrete, by means of hot-stretching thereof.

2. Description of the Prior Art As to such stretching apparatus, anapparatus has been known which is disclosed in Japanese PatentPublication No. 27704/1970, in which a pair of caterpillar assemblies,each of which is constituted by a pair of chain-rollers contacting eachother under pressure and rotating in opposite directions are spacedalong a moving steel wire or steel cable and a plurality of holdingmembers are provided on each of the chain-rollers and urged againstthose provided on the opposite chainroller by fluid pressure to hold thesteel wire or steel cable therebetween and to move it so that the steelwire or steel cable is stretched. In such apparatus, in general, thesteel wire or steel cable is stretched between the caterpillars bychanging the rotational velocities of the caterpillars.

However, since the steel wire or steel cable to be processed in suchapparatus is stretched at the input and output sides of the. respectivecaterpillars, slippage of the steel wire or steel cable may beencountered. In the above-mentioned conventional apparatus, since theholding member for holding the steel wire or steel cable is a solidstructure of metal, the possibility of the slippage of the steel wire orsteel cable is even larger and if it occurs the shoes are defaced andthe steel wire or steel cable is damaged, resulting in the defect thatgood stretching can not be performed. On the other hand, when theholding members themselves are formed of rubber in order to eliminatesuch slippage, the holding force is necessarily lowered resulting in thesame defect.

A primary object of the present invention is to provide a stretcherapparatus for hot-stretching steel wire or steel cable which canhot-stretch the steel wire or steel cable with a uniform tension loadapplied on the steel wire or steel'cable to be processed by preventingthe moving steel wire or steel cable from slipping.

Another object of the present invention is to provide a hot-stretchingapparatus for steel wire or steel cable which can apply a substantiallyconstant tension load on the steel wire or steel cable to be processedand hotstretch it uniformly by readily controlling the tension on themoving steel wire or steel cable.

Another object of the present invention is to provide an installationwhich is simple in construction and easy in operation and by which steelwire or steel cable of uniform quality with small relaxation can bemanufacthe wire or cable with exerting thereon a uniform tension load.

The present invention resides in a hot stretching apparatus comprising apair of spaced caterpillars located along the moving direction of steelwire or steel cable to be stretched, each including at least one pair ofchain-rollers which are in compressive contact with each other androtated in opposite directions. A heating apparatus is disposed at aposition between the caterpillars and a cooling apparatus is alsodisposed at an- 7 other position between the caterpillars. Onecaterpillar tured by applying a desired substantially constant tensionload on the steel wire or steel cable to be processed and hot-stretchingthe wire or cable.

SUMMARY OF THE INVENTION The present invention provides an installationwhich is easily operable and has simple construction, for manufacturingsteel wire or steel cable having small relaxation and uniform quality bypreventing the slippage of the moving steel wire or steel cable andhot-stretching is disposed forwardly of the other caterpillar in themoving direction of the steel wire or steel cable and driven at a highervelocity than that of the other caterpillar so that a predeterminedtension is applied on the moving steel wire or cable between thecaterpillars. The invention is characterized by each chain-roller of thepair including holder members which are provided in facing relation toand urged, under liquid pressure, againstthose of the otherchain-roller, and that each of the holder members has an upper partholding the steel wire or cable and a lower part physically connected tothe chain-roller, the parts being formed of metal, and that the upperpart is supported by the lower part through resilient plates.

The above and other objects and features of the present invention willbe fully understood by reading the description of the present inventionwith reference to the attached drawings, which illustrate an embodimentof the present invention although the present invention is not limitedto such embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of anembodiment of a hot-stretching apparatus of steel wire and steel cable,according to the present invention;

FIG. 2 is an enlarged front view of a portion of the embodiment in FIG.1, and

FIG. 3 is an enlarged side view of a portion of the embodiment in FIG.1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the embodimentshown in the drawings, it includes caterpillar assemblies 2 and 3, eachcomprising a pair of chain-rollers provided at spaced positions along amoving direction of steel wire or cable 1 as shown in FIG. 1. Thecaterpillar 3 is disposed forwardly of the caterpillar 2 and is drivenso that it rotates in direction shown by arrows at higher velocity thanthe caterpillar 2 by the order of 1-1.2 percent by a suitable drivingdevice. The driving device may be separate electric motors so that bothcaterpillars can simultaneously be controlled or may be a single motorin which the caterpillars may be driven simultaneously throughtransmission mechanisms. The respective caterpillars 2 and 3 haveendless chain-rollers 4 and 4' which are disposed respectively, in overand under fashion, with compressive pressure urging them into contactwith each other and are rotated in opposite directions. On thechain-rollers 4 and 4' thus disposed, a plurality of holder members 12and 12 are provided respectively as shown in FIG. 2 and the holdermembers on one chain roller are in facing relation to the holder memberson the other chain roller with a slight gap therebetween.

Each of the holder members 12' provided on the lower chain-roller 4 hasa metal upper part provided with a V-shaped holding groove 16 forholding the steel wire or cable 1 on the upper surface thereof and ametal plate secured at one surface to the upper part 15 by means ofbolts 18, the other surface of the metal plate 20 being bonded to arubber like resilient plate 17, as shown in FIG. 3. The lower surface ofthe resilient plate 17 is bonded to another metal plate 21 which isbolted to a lower metal part 14 by means of bolts 18'. The lower metalpart 14 is welded to a chain 11' of the chain-roller 4 so that theholding member 12 is rotated with the rotation of a roller 13' of thechain roller 4'.

Although the upper metal part 15 and the lower metal part 14 of theholding member 12 may be bonded directly to the resilient plate 17, itis economical and efficient to bolt the upper part 15 and the lower part14 to the metal plates 20 and 21 by means of the bolts 18 and 18,respectively, as described and to bond the metal plates 20 and 21 to theopposite surfaces of the resilient plate 17, because the provision ofthe holding member is facilitated by so doing and the upper part 15which requires precise machining and the lower part 14 welded to thechain 11 can be reused by unfastening the bolts 18 and 18 and exchangingonly the resilient plate 17 and the metal plates 20 and 21 even when theresilient plate 17 is fatigued.

The holder members 12 provided on the upper chain roller 4 areconstructed in similar manner to the lower holding members 12. Above theroller 13 of the upper chain roller 4, a plurality of horizontallyspaced liquid pressure cylinders (not shown) are provided each of whichcooperates with three or four pairs of holder members 12 and 12' througha guide rail 19 to urge the members toward each other. However, anynumber of the holder member pairs to be actuated by one liquid pressurecylinder and any number of the liquid pressure cylinders may be used.

According to the apparatus thus constructed, since the upper parts 15 ofthe holding members 12 and 12 which hold the steel wire or steel cable 1and the lower parts 14 secured to the chain rollers 4 and 4' are formedof metal and the upper parts 15 are supported through the rubber-likeresilient plates 17 by the metal lower parts 14, the resilient plates 17intermediate between the holder members 12 and 12', even when thestretching of the steel wire or cable 1 is gradually increased from theinput to the output of the caterpillar 2 and from the output to theinput of the caterpillar 3, are deformed slippingly in response to suchincreases in elongation, and thus the upper parts 15 follow the steelwire or cable 1, resulting in no slippage between the cable 1 and theupper parts 15 which hold the cable directly and in uniform holding ofthe cable 1 by the plural holder members 12 and 12 through liquidpressure. In addition to this, two or more steel wires cansimultaneously be stretched by forming two or more holding grooves onthe respective wire holding surfaces of the metal upper parts 15 whichare supported by the rubber-like resilient plates 17 provided betweenthe holder members 12 and 12'.

Returning to FIG. 1, a numeral 5 shows a support roller positionedbetween the caterpillars 2 and 3 and, between the support roller 5 andthe caterpillar 2, a pressure roller 6 is provided. The function of thepressure roller 6 is to detect the tension strength applied on the steelwire 1 between the caterpillars 2 and 3. The load or pressure exerted bythe pressure roller 6 may be about one fifth to one seventh of the totaltension and, consequently, a means for producing such load issufficiently to be small sized one. The load to be exerted on the steelwire 1 by the pressure roller 6 may be applied by a weight hanging fromthe roller 6 or a strong plate spring. However, it will be described acase where the load is applied by an oil pressure cylinder 7 as shown.

The detection and the regulation of tension on the moving steel wire orcable is generally performed by shifting the pressure roller 6 withinthe stroke range of vthe cylinder 7 and, if the roller shift is out ofthe range,

the regulation thereof becomes possible by changing the difference invelocity between the caterpillars 2 and 3 by using an automatic controldevice 8.

The same object of the present invention may be achieved without thepressure roller 6 by fixing the velocity difference between thecaterpillars 2 and 3 after the difference, that is, the standing tensioncondition of the steel wire or steel cable is determined by theseregulation devices.

Numeral 9 shows a heating device which is provided between the pressureroller 5 and the caterpillar 3 and functions to heat the steel wire to300400 C. As the heating method, high frequency induction heating,electric resistance heating or a hot-air, heating etc. may be used asdesired. A conventional cooling device such as spray 10 is providedbetween the heating device 9 and the caterpillar 3 and functions to coolthe steel wire 1 heated by the heater 9. In this case the steel wire 1is merely in contact with the support roller 5 and the pressure roller6.

In this manner, the steel wire 1 is permanently stretched between thecaterpillars 2 and 3 and the relaxation properties of the wire isimproved.

Thus, the apparatus according to the present invention is simple inconstruction and unexpensive in installation and, by the apparatus theregulation of tension is facilitated. For the steel cable, it is easy tounload the same when the joints pass through the apparatus.

As described hereinbefore, the present invention has an advantage thatthe steel wire or cable can be stretched with uniform load because ofthe special construction of the chain-rollers of the caterpillars of thehot-stretching apparatus for steel wire or cablewhich prevents themoving steel wire or cable from slipping and of the provision of thepressure roller which is simple in construction and can desirablyregulate the urging pressure on the steel wire or cable and thus thetension on the wire or cable.

What is claimed is:

1. In an apparatus for hot stretching steel wire comprising: a pair oflongitudinally spaced caterpillar assemblies located with a spacetherebetween along the path of movement of a steel wire to be stretched,each caterpillar assembly including a pair of chain-rollers whichcompressively contact each other and rotate in opposite directions, aheating device disposed longitudinally at a position between thecaterpillar assemblies, one caterpillar assembly disposed forwardly ofthe other caterpillar assembly in the moving direction of the steel wireand being driven at a higher velocity than that of the other caterpillarassembly so that a predetermined, high tension is applied to the movingsteel wire between the caterpillar assemblies sufficient to effectstretching of said wire, the improvement wherein: each said wirerelative to said first parts which grip the wire on either side thereof.

2. The apparatus for hot stretching for steel wire and cable as setforth in claim 1, further comprising a pressure roller and a supportroller provided longitudinally between said other caterpillar assemblyand the heating device and contacting said wire or cable with saidpressure roller including means for regulating the tension exerted onthe steel wire being processed.

1. In an apparatus for hot stretching steel wire comprising: a pair oflongitudinally spaced caterpillar assemblies located with a spacetherebetween along the path of movement of a steel wire to be stretched,each caterpillar assembly including a pair of chain-rollers whichcompressively contact each other and rotate in opposite directions, aheating device disposed longitudinally at a position between thecaterpillar assemblies, one caterpillar assembly disposed forwardly ofthe other caterpillar assembly in the moving direction of the steel wireand being driven at a higher velocity than that of the other caterpillarassembly so that a predetermined, high tension is applied to the movingsteel wire between the caterpillar assemblies sufficient to effectstretching of said wire, the improvement wherein: each longitudinallyaligned chain roller of the pair includes a plurality of holder membersin facing relation to and urged under liquid pressure against those ofthe opposite chain roller, each of said holder members having a firstpart frictionally gripping opposite sides of the steel wire and a secondpart connected to the chain roller, said parts being formed of metal,and said first parts being fixed to said second parts respectivelythrough resilient plates which permit relative shifting between firstand second parts in the direction of wire travel under applied tensionbut which prevents Slippage of said wire relative to said first partswhich grip the wire on either side thereof.
 2. The apparatus for hotstretching for steel wire and cable as set forth in claim 1, furthercomprising a pressure roller and a support roller providedlongitudinally between said other caterpillar assembly and the heatingdevice and contacting said wire or cable with said pressure rollerincluding means for regulating the tension exerted on the steel wirebeing processed.